Aerosol-generating device

ABSTRACT

An aerosol-generating device includes a pump. The pump includes a first pump chamber and a second pump chamber on opposing sides of a separation element. Each of the first pump chamber and the second pump chamber have an inlet valve and an outlet valve configured to establish a pumping direction. The pump also includes a first actuator and a second actuator. The first actuator is associated with the first pump chamber and the second actuator is associated with the second pump chamber. The first actuator and the second actuator are each configured to change a chamber volume of the respective pump chamber. The pump further includes a common inlet, and a common outlet. The common inlet and common outlet are in fluid communication with the first pump chamber and the second pump chamber and are configured to establish a flow direction. The pumping direction is aligned with the flow direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/241,043, filed on Jan. 7, 2019, which is a continuation of U.S.application Ser. No. 15/675,164, filed on Aug. 11, 2017, which is acontinuation of, and claims priority to, international application no.PCT/EP2017/068691, filed on Jul. 24, 2017, and further claims priorityunder 35 U.S.C. § 119 to European Patent Application No. 16184283.6,filed Aug. 16, 2016, the entire contents of each of which areincorporated herein by reference.

BACKGROUND Field

At least one example embodiment relates to an aerosol-generating device,such as an aerosol-generating device including a micropump.

Description of Related Art

In aerosol-generating devices a liquid may be vaporized and/or atomizedin an atomizer. The atomizer may include a heating element arranged nextto an opening of a reservoir containing the liquid. The liquid may betransported to the atomizer by capillary action of a capillary material.

SUMMARY

At least one example embodiment relates to an aerosol-generating device.

In at least one example embodiment, an aerosol-generating devicecomprises a reservoir configured to hold an aerosol-forming substrate,an atomizer configured to atomize the aerosol-forming substrate, and amicropump between the reservoir and the atomizer. The micropump is influid connection with the reservoir and the atomizer. The micropump isconfigured to supply the aerosol-forming substrate from the reservoir tothe atomizer. The micropump includes two pump chambers, each of the twopump chambers having a chamber volume, and each of the two pump chambersincluding, at least one inlet valve, and at least one outlet valve. Theat least one inlet valve and the at least one outlet valve areconfigured to establish a pumping direction. The micropump also includestwo actuators, a common inlet, and a common outlet. Each of the twoactuators is assigned to a respective one of the two pump chambers. Eachof the two actuators is configured to change the chamber volume of therespective one of the two pump chambers. The two pump chambers arearranged in parallel and in fluid connection with the common inlet andthe common outlet. The two actuators are configured to operate inparallel such that a volume change in each of the two pump chambersoccurs simultaneously for both pump chambers.

In at least one example embodiment, the two pump chambers are in directfluid connection with the common inlet and the common outlet.

In at least one example embodiment, each of the two pump chambers isarranged opposite to a respective one of the two actuators.

In at least one example embodiment, the two pump chambers and the twoactuators are configured such that a same volume change in each of thetwo pump chambers occurs upon operation of the two actuators.

In at least one example embodiment, the chamber volume of each of thetwo pump chambers is identical.

In at least one example embodiment, a flow rate through the micropumpranges from about 1 μL/s to about 7 μL/s.

In at least one example embodiment, each of the two actuators is a piezomembrane actuator.

In at least one example embodiment, the micropump comprises two inletvalves and two outlet valves per pump chamber.

In at least one example embodiment, the micropump is generally symmetricabout a plane arranged parallel to and between the two pump chambers.

In at least one example embodiment, an inlet connection of the commoninlet and an outlet connection of the common outlet are at a same sideof the micropump.

In at least one example embodiment, the aerosol-generating devicefurther comprises a flow sensor connected to a control circuit, thecontrol circuit configured to control a fluid flow in the micropump.

In at least one example embodiment, the atomizer comprises at least oneof an acoustic atomization element, an ultrasonic vibrator, or avaporizer. In at least one example embodiment, the vaporizer includes aheater.

In at least one example embodiment, the aerosol-forming substrateincludes at least one of a nicotine containing aerosol-forming substrateor a tobacco flavour containing aerosol-forming substrate.

In at least one example embodiment, the aerosol-forming substrate is aviscous liquid having a viscosity ranging from about 1 mPas and 200mPas. In at least one example embodiment, the viscous liquid has aviscosity ranging from about 1 mPas to about 150 mPas.

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments will now be described, by way of example only, withreference to the accompanying drawings.

FIG. 1 is an exploded view of a micropump having two serially arrangedactuators showing exemplary parts of the micropump according to at leastone example embodiment.

FIG. 2 is an illustration of a micropump with parallel actuatorsaccording to at least one example embodiment.

FIG. 3 is a schematic view of an aerosol-generating system including amicropump according to at least one example embodiment.

DETAILED DESCRIPTION

Example embodiments will become more readily understood by reference tothe following detailed description of the accompanying drawings. Exampleembodiments may, however, be embodied in many different forms and shouldnot be construed as being limited to the example embodiments set forthherein. Rather, these example embodiments are provided so that thisdisclosure will be thorough and complete. Like reference numerals referto like elements throughout the specification.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a”, “an” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. It willbe further understood that the terms “comprises,” “comprising,”“includes,” and/or “including,” when used in this specification, specifythe presence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

It will be understood that when an element or layer is referred to asbeing “on”, “connected to” or “coupled to” another element or layer, itcan be directly on, connected or coupled to the other element or layeror intervening elements or layers may be present. In contrast, when anelement is referred to as being “directly on”, “directly connected to”or “directly coupled to” another element or layer, there are nointervening elements or layers present. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, components, regions, layersand/or sections, these elements, components, regions, layers and/orsections should not be limited by these terms. These terms are only usedto distinguish one element, component, region, layer or section fromanother region, layer or section. Thus, a first element, component,region, layer or section discussed below could be termed a secondelement, component, region, layer or section without departing from theteachings set forth herein.

Spatially relative terms, such as “beneath”, “below”, “lower”, “above”,“upper”, and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the example term “below” can encompass both anorientation of above and below. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly.

Example embodiments are described herein with reference to cross-sectionillustrations that are schematic illustrations of idealized embodiments(and intermediate structures). As such, variations from the shapes ofthe illustrations as a result, for example, of manufacturing techniquesand/or tolerances, are to be expected. Thus, these example embodimentsshould not be construed as limited to the particular shapes of regionsillustrated herein, but are to include deviations in shapes that result,for example, from manufacturing. For example, an implanted regionillustrated as a rectangle will, typically, have rounded or curvedfeatures and/or a gradient of implant concentration at its edges ratherthan a binary change from implanted to non-implanted region. Likewise, aburied region formed by implantation may result in some implantation inthe region between the buried region and the surface through which theimplantation takes place. Thus, the regions illustrated in the figuresare schematic in nature and their shapes are not intended to illustratethe actual shape of a region of a device and are not intended to limitthe scope of this disclosure.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art. It will be further understood that terms,such as those defined in commonly used dictionaries, should beinterpreted as having a meaning that is consistent with their meaning inthe context of the relevant art and this specification and will not beinterpreted in an idealized or overly formal sense unless expressly sodefined herein.

Unless specifically stated otherwise, or as is apparent from thediscussion, terms such as “processing” or “computing” or “calculating”or “determining” or “displaying” or the like, refer to the action andprocesses of a computer system, or similar electronic computing device,that manipulates and transforms data represented as physical, electronicquantities within the computer system's registers and memories intoother data similarly represented as physical quantities within thecomputer system memories or registers or other such information storage,transmission or display devices.

At least one example embodiment relates to an aerosol-generating device.The device comprises a reservoir configured to hold an aerosol-formingsubstrate and an atomizer configured to atomize the aerosol-formingsubstrate. The device further comprises a micropump between thereservoir and the atomizer and in fluid connection with the reservoirand the atomizer. The micropump is configured to supply theaerosol-forming substrate from the reservoir to the atomizer. Themicropump comprises two pump chambers having two separate chambervolumes and two actuators. Each actuator is assigned to one of the twopump chambers for changing a respective chamber volume. Each pumpchamber is provided with at least one inlet valve and at least oneoutlet valve, which are configured to establish a pumping direction. Themicropump further comprises a common inlet and a common outlet. The twopump chambers are arranged in parallel and are in fluid connection withthe common inlet and the common outlet. The actuators are configured tooperate in parallel such that a volume change in each of the two pumpchambers occurs substantially simultaneously for both pump chambers. Inat least one example embodiment, control electronics present in theaerosol-generating device may control the micropump and/or the actuatorsof the micropump respectively.

By operating the actuators substantially simultaneously, and havingsubstantially same volume changes by an actuator stroke of each of theactuators, a pumping pressure may basically be doubled compared tohaving only one pumping chamber. A pumping pressure may also besubstantially doubled compared to, for example, two pumps connected inseries. Such single or serial micropumps are available from BartelsMikrotechnik GmbH, with the Bartels mp5 micropump having one actuatorand the Bartels mp6 micropump having two actuators in two seriallyarranged pump chambers.

Arranging two pump chambers in parallel also allows for a substantiallyhigh performance of the micropump and high flow rates of viscous fluids.Since increased and/or maximum flow rates typically decrease with higherviscosity fluids, two pump chambers at higher pumping pressure allow forwell-defined high flow rates also for viscous or high viscous fluids.

A parallel arrangement of two pump chambers also facilitates a compactand small design of the micropump and of the aerosol-generating devicethe micropump is used in. This is in particular suitable for hand-helddevices, where space is limited and the device should be miniaturized.Such hand-held devices may, for example, be inhalators for medicalpurposes or vaping or smoking devices. Such hand-held devices may, forexample, be vaping devices wherein an e-liquid is vaporized, and thee-liquid is viscous.

The actuators of the micropump may be driven by control electronicsconnected to the micropump. The control electronics may be combined withcontrol electronics of the aerosol-generating device the control theaerosol-generating device.

The actuators may be piezo membrane actuators, mechanical actuators,thermal actuators, magnetic actuators, or other suitable actuators thatresult in a volume change of a pump chamber. In at least one exampleembodiment, disk- or plate-shaped actuators are used. In at least oneexample embodiment, two piezo membrane actuators are used in themicropump.

In piezo membrane actuators, the amplitude of the voltage applied to theactuator defines the strokes of the actuator and therefore thedisplacement of the pumped medium per pump cycle. With rising amplitudeof a controller voltage, the flow rate rises substantially linearly to adesired and/or maximum flow rate.

The flow rate also increases linearly in a defined frequency range. Thefrequency determines the number of pump strokes per unit of time. Afterreaching a desired and/or a maximum flow rate at the resonancefrequency, the flow rate decreases again with higher frequencies abovethe resonant point.

The combination of signal, amplitude and frequency defines theperformance of the micropump. Operation parameters may be chosen basedon the fluid to be transported by the micropump.

Each pump chamber of the micropump comprises at least one inlet valveand at least one outlet valve. In at least one example embodiment, eachpump chamber comprises two inlet valves and two outlet valves. Twovalves per pump chamber may provide a high reliability of operation ofthe micropump.

In operation, a fluid, such as the aerosol-generating substrate, flowsalong a fluid path from the common inlet towards the common outlet, andthrough each of the two pump chambers via their respective inlet valvesand outlet valves. That is, the fluid path can be defined as a route ora trajectory the fluid follows as it is being transported in themicropump. In at least one example embodiment, the valves are arrangedand designed in such a manner that direction changes of a fluid streamalong the fluid path being invoked by the valves are reduced and/orminimized. Thus, energy for the transport of the fluid is reduced and/orminimized and additionally, the settling of gas bubbles is reduced.Moreover, a smoother fluid path may reduce turbulence and lessen theamount of fluid impingement upon the walls of the micropump, therebyhelping to reduce the amount of mechanical vibration and noise. In atleast one example embodiment, changes of angles in the fluid path arenot abrupt. In at least one example embodiment, the fluid path comprisesno angles of 90 degree or smaller. In at least one example embodiment,the design of the pump chambers and their respective valves ensures thatthe fluid flows through the valves at an obtuse angle. In at least oneexample embodiment, the direction of flow of fluid from the common inletto the common outlet, along the fluid path, does not change by 90degrees or more. In at least one example embodiment, holes in deviceelements of the micropump connecting different fluid planes comprisediameters equal to or larger than a length of the holes.

In at least one example embodiment, the two pump chambers are in directfluid connection with the common inlet and with the common outlet. Thus,each pump chamber is directly connected to the common inlet and thecommon outlet without intermediate fluid channels. In at least oneexample embodiment, the fluid connections of the pump chambers andcommon inlet or common outlet are separated solely by the at least oneinlet valve or the at least one outlet valve, respectively, of the pumpchambers.

In the device the two pump chambers as well as the two actuators may bearranged substantially opposite each other. In at least one exampleembodiment, the two actuators and the two pump chambers are arrangedexactly opposite each other. Such an arrangement facilitates themanufacture of the micropump and allows for the manufacture of a verycompact micropump.

The two pump chambers and the two actuators may be configured such thata same volume change in each of the two pump chambers occurs uponoperation of the two actuators.

The chamber volumes of the two pump chambers do not have to have a samesize and may be different. However, in at least one example embodiment,the chamber volumes of the two pump chambers are identical.

In at least one example embodiment, the components which are requiredfor the production of one pump chamber of the micropump, particularlythe valve(s) and the actuator are designed to be substantiallyinterchangeable with, or identical to the components for the second pumpchamber of the same micropump. That is, all actuators, valves andoptionally other components that are present in one pump chamber aredesigned identical to those of the other pump chamber. By this, the riskof confusion during assembly is reduced and the production cost may bereduced and/or minimized.

In at least one example embodiment, the micropump comprises a symmetricset-up in view of a plane arranged parallel to and between the two pumpchambers.

A symmetric and in particular an identical set-up of the two pumpchambers allow for a simplified control and operation of the micropump.

This symmetric set-up may include the common inlet and common outlet.Thus an inlet connection of the common inlet may be arranged at one sideof the micropump and an outlet connection of the common outlet may bearranged at an opposite side of the micropump. However, an inletconnection of the common inlet and an outlet connection of the commonoutlet may also be arranged at a same side of the micropump. This allowsthe manufacture of an even more compact micropump.

In at least one example embodiment, all components which are in contactwith the fluid consist of a same material. In at least one exampleembodiment, the pump chambers, valves, and common inlet and outlet aremanufactured from a same material. Such a material may be adapted to thephysical and chemical characteristics of a fluid to be pumped. In atleast one example embodiment, all components which are in contact withthe fluid may consist of polyphenylene sulphone (PPSU). This material isuseful for the joining and fabrication techniques that may be used toinstall the micropump in the device. Other suitable materials may beused, for example polypropylene (PP) or polyimide (PI). In at least oneexample embodiment, the parts that are in contact with the fluid may becoated, for example, by biocompatible or other particularly inertmaterials, in order to adapt the device to specific requirements. Alsoother materials such as silicon, metals, and/or glasses may be used,wherein it should be ensured in the case of materials having only a lowstretchability that the actuators can still lead to a change of thechamber volume.

All components of the micropump that must be joined to each other canfor example be joined by suitable adhesives or by laser welding. Thelatter technique is suitable in particular for the joining of plasticsand offers, short production times, and the possibility of producing ashermetically tight connection without adhesives that comes close to thestrength of the source material.

In at least one example embodiment, the micropump comprises thefollowing elements, which sequence basically corresponds to an assemblysequence. The micropump comprises two base elements each comprising arecess and half of an inlet and half of an outlet, two actuators withelectrodes and electric terminals, each of the actuators arranged in oneof the recesses, two protection layers arranged over each of theactuators, the protection layers each forming one side of a pumpchamber, valve foils which are insertable into the recesses and whichcarry the movable parts of the inlet and outlet valves of the pumpchambers, and two intermediate layers which are also insertable into therecesses and which have openings which form the immobile parts of theinlet and outlet valves. The intermediate layers form together with therespective protection layers and recess side walls the pump chambers.

Actuator and protection foil as well as valve foil and intermediate foilmay be kept in place by seals, for example by weld seals or an adhesiveseal.

Upon positioning of a flow separation element at a position in betweenthe inlet and outlet and in between the two base elements, the two baseelements may be put together and assembled. In at least one exampleembodiment, the two base elements are provided with a fluid-tightsealing formed by laser welding, and the recesses of the two baseelements are closed in such a manner that the components in the interiorof the base elements are protected from environmental influences. Uponassembly, each of the two halves of the inlet and outlet are alsocombined and form the common inlet and the common outlet, and thecorresponding inlet connection and the outlet connection, which allowthe micropump to connect to a reservoir and to the atomizer or tocorresponding tubings connected to the reservoir and to the atomizer,respectively.

The aerosol-generating device may further comprise a flow sensorconfigured to control a fluid flow in the common outlet of themicropump. The flow sensor is connected to the control electronics whichare configured to control the fluid flow by, for example, keeping thefluid flow constant, and/or by changing the micropump parameters ifrequired. The device may thus comprise a controlled loop system.

The atomizer of the device may be designed to atomize and/or vaporizethe aerosol-forming substrate by any suitable means, mechanisms, and/ormethods. In at least one example embodiment, the atomizer may vaporizethe aerosol-forming substrate by heat, and/or may atomize or nebulizethe aerosol-forming substrate by ultrasound or other vibration means.The atomizer may comprise any one or a combination of an acousticatomization element, an ultrasonic vibrator, a vaporizer such as aheater or any other atomizer.

The device may comprise any fluid to be atomized. The aerosol-formingsubstrate may be gas or liquid or a combination thereof. In at least oneexample embodiment, the aerosol-forming substrate is a liquid. However,the aerosol-forming substrate may originally also be a solid, which isliquefied, for example by heating, such that the liquid may betransported by the micropump to the atomizer.

The aerosol-forming substrate may, for example, comprise medicine,flavour or stimulating substances.

Liquid aerosol-forming substrate may comprise at least one aerosolformer and a liquid additive.

The aerosol-former may, for example, be propylene glycol or glycerol.

The liquid aerosol-forming substrate may comprise water.

In at least one example embodiment, the aerosol-forming substrate is ane-liquid to be used in vaping systems.

In at least one example embodiment, the liquid additive may be any oneor a combination of a liquid flavour or liquid stimulating substance.Liquid flavour may, for example, comprise tobacco flavour, tobaccoextract, fruit flavour or coffee flavour. The liquid additive may, forexample, be a sweet liquid such as for example vanilla, caramel andcocoa, a herbal liquid, a spicy liquid, or a stimulating liquidcontaining, for example, caffeine, taurine, nicotine or otherstimulating agents known for use in the food industry.

The device comprises one or a combination of nicotine containingaerosol-forming substrate and tobacco flavour containing aerosol-formingsubstrate.

In at least one example embodiment, the device comprises a viscousliquid aerosol-forming substrate having a viscosity ranging from about 1mPas to about 200 mPas, about 1 mPas to about 150 mPas, or about 80 mPasto about 130 mPas.

In at least one example embodiment, the aerosol-generating device is anelectronic smoking device as used in electronic smoking systems or anelectronic vaping device. The smoking device and/or the vaping devicemay be a hand-held device. The device may be a smoking system whereintobacco is heated rather than combusted.

In at least one example embodiment, a chamber volume of the micropumpranges from about 1 ml to about 2 ml, a flow rate of the micropumpranges from about 1 μL/s to about 7 μL/s, a pumping pressure of themicropump ranges from about 500 mBar to about 700 mBar, and a size ofthe micropump (without connectors) is about 14×14×6.5 mm³.

In at least one example embodiment, the micropump has a frequencyranging from about 0 Hz to about 300 Hz, and a peak-to-peak voltage ofup to about 320 Vpp. The micropump may have a sinusoidal, rectangular,or intermediately shaped actuator voltage curve. In at least one exampleembodiment, lifting and lowering phases of the actuator are notidentical. In at least one example embodiment, an actuator voltage curveis adapted in order to improve and/or optimize the micropump in view ofnoise and bubble generation at a given flow rate and viscosity of afluid.

FIG. 1 is an exploded view of a micropump having two serially arrangedactuators showing exemplary parts of the micropump according to at leastone example embodiment.

FIG. 1 is an exploded view of a Bartels mp6 micropump as described in USpatent application US 2011/0005606, the entire content of which isincorporated herein by reference thereto. The micropump 1′ includes alayered assembly, which comprises two serially arranged pump chambers 2.In FIG. 1, the assembly 1′ includes the following components: a baseelement 7, a valve foil 8, an intermediate layer 9, a protection layer10, two actuators 6 and a lid element 11.

The base element 7 is made of a plastic. The base element 7 comprises arecess 7′ into which all subsequent components are inserted. The baseelement 7 also includes inlet 4 and exit 5 which are provided for thedelivery of the fluid, and which, as depicted here, are for exampledesigned as a hose-like connector. Other connector types which areadapted to the respective application may be used. The base element 7also comprises parts of the fluid channels for the valves 3, which areproduced by injection moulding, and therefore, in the same process asthe base element itself. The base element 7 includes projecting parts 7″having a same shape as mounting aids 7″′, which are arranged in such amanner that they cooperate with the recesses of the mounting aid 7″′.The assembly of subsequent components such as the valve foil 8 can onlyoccur in one certain way, so that an incorrect mounting is excluded to alarge extent.

The valve foil 8 includes the movable parts of the valves 3. The valvefoil 8 is inserted into the base element 7. In at least one exampleembodiment, the valve foil 8 comprises the movable parts of the inletvalves 3′ of each pump chamber, as well as the movable parts of therespective outlet valves 3″. Furthermore, the valve foil 8 alsocomprises the recesses of the mounting aid 7″′ which aid in theinsertion of the valve foil 8 into the base element 7.

The intermediate layer 9 is made of plastic, and is designed in such amanner that it can be inserted into the recess 7′ of the base element 7.In the centre of each pump chamber 2, which is respectively formed by arecess in the intermediate layer, one respective opening 9′ is locatedthrough which fluid can flow into the respective pump chamber and/or outof the same.

The protection layer 10 is applied onto the intermediate layer and thusfluidically borders the pump chamber. The protection layer should befirmly connected with the intermediate layer 9, so that fluid cannotexit or flow over a circumference thereof nor in the region between thepump chambers. In at least one example embodiment, penetration laserwelding is used to connect the protection layer 10 and the intermediatelayer 9. Alternative production techniques may include gluing,ultrasound welding, or mechanical clamping of the respective components.

Two actuators 6 are provided as disc shaped piezo-actuators in theexample embodiment shown. Each of the actuators is geometrically adaptedto the pump chamber 2 which is arranged below, and the actuators includeelectrodes 6′ for establishing electrical connections. Connected tothese is an electric terminal 6″ which can be led out of the housing ofthe assembly 1′, and which provides a sufficient number of individualwires for the connection of each actuator 6.

The lid element 11 serves as a seal of the housing of the apparatus. Thelid element 11 covers at portion of the base element 7. In at least oneexample embodiment, the lid element 11 is also fabricated from plasticand is designed such that it can be connected with the base element 7 bypenetration laser welding.

FIG. 2 is an illustration of a micropump with parallel actuatorsaccording to at least one example embodiment.

In at least one example embodiment, as shown in FIG. 2, a micropump 201with two actuators 206 arranged in parallel. The micropump 201 is alayered assembly, wherein the basic elements of one pump chamber may besimilar or the same as one individual pump chamber and actuator asdescribed with respect to FIG. 1.

In FIG. 2, two base elements 207 each comprise a recess into which allcomponents forming one pump chamber are inserted. The two base elements207 each include an inlet housing portion 240 and an outlet housingportion 250. When the two base elements 207 are assembled, the inlethousing portions 240 form a common inlet 204, and the outlet housingportions 250 form a common outlet 205. The inlet 204 and the outlet 205may be connected to tubings 244, 255, for example plastic hoses, for thedelivery of fluid to the micropump and away from the micropump 201.

In at least one example embodiment, the two actuators 206 are discshaped piezo-actuators. One actuator is inserted into a recess of arespective base element 207. The piezo-actuators may, for example, be apiezo ceramic mounted on a brass membrane, which piezo ceramic deformsthe membrane when a voltage is applied to the piezo ceramic.

Each of the actuators 206 is sized and configured to mate fit within thegeometry and size of the recess into which each actuator 206 is placed,and which basically defines the lateral extensions of the pump chambers202, which are arranged below or above each actuator 206. The actuators206 are connected to electrodes and comprise wiring 260 to formelectrical contacts of the actuators. The wiring 260 leads out of thehousing of the micropump 201.

The micropump also includes two protection layers 210, for example aKapton tape, which are provided in the recess of each base element 207.Each protection layer 210 forms one side of a pump chamber 202. Theprotection layer 210 transmits movement of the piezo actuator into thepump chamber 202. The protection layer 210 is held in place by a seal295, for example a weld seal, clamping, or an adhesive seal, alsosealing the pump chamber 202.

An intermediate layer 290, which may be formed of plastic, is insertedinto each of the respective recesses of the base elements 207. Theintermediate layers 290 carry the valve foils and are held in place byanother seal 295, such as for example a weld seal, also sealing the pumpchamber 202. The space between intermediate layer 290 and protectionlayer 210 and the recess walls defines the size of the pump chamber 202.

Off center in the intermediate layer 290 in the direction of the inlet204, an inlet opening 291 is located, through which fluid can flow fromthe common inlet 204 into the respective pump chamber 202. Off center inthe intermediate layer 290 into the direction of the outlet 205 anoutlet opening 292 is located, through which fluid can flow from therespective pump chamber 202 into the common outlet 205. In the center ofthe intermediate layer 290 a flow separation element 298 is arranged.

One flow separation element 298 is used for both pump chambers, and isarranged between the two pump chambers separating the common inlet 204from the common outlet 205 in view of a flow direction. A flow of fluid200 from the common inlet 204 towards the common outlet 205 defines afluid path, shown as the arrows in FIG. 2. The fluid path is showncomprising no angles of 90 degree or smaller, i.e. the flow pathcomprises only obtuse angles, because the flow separation element 298has a shape and structure to support a smooth fluid flow from the commoninlet 204 through the inlet valves 230 and from the outlet valves 231into the common outlet 205.

A first valve foil 280 comprises the movable parts of the inlet valve orvalves 230 of each pump chamber 202. A second valve foil 281 comprisesthe movable parts of the respective outlet valves 231. The first valvefoil 280 may be attached to the intermediate layer 290. The second valvefoil 281 may be attached to the flow separation element 298.

By parallel and synchronous actuation of the piezo actuators 206, adeformation draws back the protective foils 210. Due to the generatedpressure change upon a draw on the aerosol-generating device, the inletvalves 230 open, and the fluid flows from the common inlet 204 to passinto the respective pump chambers 202. An actuation of the piezoactuators into the opposite direction compress the pump chambers 202 dueto the flexibility of the protective layers 210 and push the fluid fromthe pump chambers 202 through the pushed open outlet valves 231 out ofthe pump chambers 202 and into the common outlet 205. Due to thearrangement of the valves, inlet valves 230 are automatically closedwhen outlet valves 231 are opened and vice versa.

In at least one example embodiment, the pump chambers 202 have a samechamber volume and a same chamber geometry.

The micropump 1 of FIG. 1 is symmetric with respect to a virtual middleplane arranged between and parallel to the two actuators 6, andextending through the common inlet and common outlet. Such aconstruction allows the manufacture of the micropump with few partsonly, by two identical individual micropump halves comprising one baseelement and pump chamber.

FIG. 3 is a schematic view of an aerosol-generating device including amicropump according to at least one example embodiment.

In at least one example embodiment, an aerosol-generating device 300includes a cartridge 315 and a battery section 305. The cartridge 315may include a mouthpiece 310, a reservoir 320 configured to contain theaerosol-forming substrate, the micropump 301, and an atomizer 330. Themicropump 301 may be the micropump of FIG. 1 or FIG. 2. The batterysection 305 includes a battery 340, control circuitry 350, and a sensor360.

In at least one example embodiment, in use, a draw is taken on themouthpiece 310. The sensor 360 senses the draw. The control circuitry350 then activates the micropump 1 and/or the atomizer 330. Themicropump is configured to supply the aerosol-forming substrate from thereservoir to the atomizer. The micropump includes two pump chambers,each of the two pump chambers having a chamber volume, and each of thetwo pump chambers including, at least one inlet valve, and at least oneoutlet valve. The at least one inlet valve and the at least one outletvalve are configured to establish a pumping direction. The micropumpalso includes two actuators, a common inlet, and a common outlet. Eachof the two actuators is assigned to a respective one of the two pumpchambers. Each of the two actuators is configured to change the chambervolume of the respective one of the two pump chambers. The two pumpchambers are arranged in parallel and in fluid connection with thecommon inlet and the common outlet. The two actuators are configured tooperate in parallel such that a volume change in each of the two pumpchambers occurs simultaneously for both pump chambers.

The specific example embodiments described above illustrate but do notlimit the invention. It is to be understood that other exampleembodiments may be made and the example embodiments described herein arenot exhaustive.

I claim:
 1. An aerosol-generating device comprising: a pump including, afirst pump chamber and a second pump chamber, each of the first pumpchamber and the second pump chamber having an inlet valve and an outletvalve configured to establish a pumping direction, a common inlet, and acommon outlet, the common inlet and the common outlet being in fluidcommunication with the first pump chamber and the second pump chamberand being configured to establish a flow direction, the pumpingdirection aligned with the flow direction.
 2. The device of claim 1,further comprising: a first actuator and a second actuator, the firstactuator being associated with the first pump chamber and the secondactuator being associated with the second pump chamber.
 3. The deviceaccording to claim 2, wherein the first pump chamber and the second pumpchamber are each arranged opposite to a respective one of the firstactuator and the second actuator.
 4. The device according to claim 2,wherein the first actuator is configured to operate in parallel with thesecond actuator.
 5. The device according to claim 2, wherein the firstpump chamber, the second pump chamber, the first actuator and the secondactuator are configured such that generally a same volume change in eachof the first pump chamber and the second pump chamber occurs uponoperation of each of the first actuator and the second actuator.
 6. Thedevice according to claim 2, wherein the first actuator and the secondactuator are piezo membrane actuators.
 7. The device according to claim1, wherein chamber volumes of the first pump chamber and the second pumpchamber are generally identical.
 8. The device according to claim 1,wherein a flow rate through the pump ranges from about 1 μL/s to about 7μL/s.
 9. The device according to claim 1, wherein the first pump chamberand the second pump chamber each includes two inlet valves and twooutlet valves.
 10. The device according to claim 1, wherein the pump isgenerally symmetric about a plane arranged parallel to and between thefirst pump chamber and the second pump chamber.
 11. The device accordingto claim 1, wherein the first pump chamber and the second pump chamberare arranged in parallel.
 12. The device according to claim 1, whereinan inlet connection of the common inlet and an outlet connection of thecommon outlet are at a same side of the pump.
 13. The device accordingto claim 1, further comprising: a flow sensor; and a control circuitconfigured to control a fluid flow in the pump based on output from theflow sensor.
 14. The device according to claim 1, further comprising: areservoir configured to hold an aerosol-forming substrate; and anatomizer configured to vaporize, atomize, or both vaporize and atomizethe aerosol-forming substrate, the pump disposed between the reservoirand the atomizer and in fluid communication with the reservoir and theatomizer.
 15. The device according to claim 14, wherein theaerosol-forming substrate includes a nicotine containing aerosol-formingsubstrate, a tobacco flavour containing aerosol-forming substrate, orboth a nicotine containing aerosol-forming substrate and a tobaccoflavour containing aerosol-forming substrate.
 16. The device accordingto claim 14, wherein the aerosol-forming substrate is a viscous liquidhaving a viscosity ranging from about 1 mPas and 200 mPas.
 17. Thedevice according to claim 16, wherein the viscous liquid has a viscosityranging from about 1 mPas to about 150 mPas.
 18. The device according toclaim 14, wherein the atomizer includes an acoustic atomization element,an ultrasonic vibrator, a vaporizer, or any combination thereof.
 19. Thedevice according to claim 18, wherein the atomizer includes thevaporizer, and the vaporizer includes a heater.
 20. The device accordingto claim 1, wherein an inlet connection of the common inlet and anoutlet connection of the common outlet are at different sides of thepump.